Automatic noncompression starting device



Sept. 3, 1968 HARUO lsODA 3,399,659

AUTOMATIC NONCOMPRESSION STARTING DEVICE Filed Oct. 24, 1966 2 Sheets-Sheet 1 20 /2 H6. H /7 /4 9 /0 4 2/ I A93 Sept. 3, 1968 HARUO [SODA 3,399,659

AUTOMATIC NONCQMPRESSION STARTING DEVICE Filed Oct. 24, 1966 2 Sheets-Sheet 2 United States Patent 3,399,659 AUTOMATIC NONCOMPRESSION STARTING DEVICE Haruo Isoda, Tokyo, Japan, assignor to Tadao Yamaoka, Ashiya-shi, Japan Filed Oct. 24, 1966, Ser. No. 588,805 2 Claims. (Cl. 123-182) ABSTRACT OF THE DISCLOSURE A noncompression starting device made integrally with a valve rocker arm chamber of an engine wherein a diaphragm having a spindle directly engageable with an exhaust valve rocker arm is normally urged by a spring acting on one side of the diaphragm so as to press the rocker arm and hence the exhaust valve to an open or noncompression position. Lubricating oil is introduced on the other side of the diaphragm, and when the engine is cranked to a predetermined revolution, the pressure of the lubricating oil overcomes the spring biasing force, thus releasing the noncompressive state of the engine and permitting the engine to start.

The present invention relates to starting devices for internal combustion engines.

In the past, internal combustion engines and particularly small diesel engines have been started by operating a noncompression lever by hand to place the engine in a state free from the loading due to compression, cranking the engine in this state manually or by an electric motor, and then turning the noncompression lever to its inoperative position as soon as the fly wheel obtains an appropriate momentum. Thus, the starting of an engine, has required a high level of skill to operate the noncompression lever accurately at proper instants.

The present invention has for its object to facilitate the starting of an engine and provides an automatic noncompression starting device for an internal combustion engine comprising means for normally maintaining the engine in a noncompressive state and means for automatically releasing the noncompressive state at the instant when the engine rotation has reached a predetermined level.

According to the present invention, there is provided an automatic noncompression starting device for starting an internal combustion engine, which comprises means for normally maintaining the engine in a noncompressive state, hydraulic pressure means for automatically releasing said noncompressive state when the engine rotation has reached a predetermined level and means for adjusting a variation of the operating fluid pressure acting upon said hydraulic pressure means.

Still according to the present invention, there is provided an automatic noncompression starting device of the type described above in which said means for maintaining the engine in a noncompressive state and said hydraulic pressure means are provided in the form of fluid pressure operating means provided integrally with a valve rocker arm chamber and acting directly on an exhaust valve rocker arm.

Still according to the present invention, there is provided an automatic noncompression starting device of the type specified in which said fluid pressure operating means comprises a housing, a diaphragm dividing said housing into two compartments, a spindle connected to said diaphragm, spring means disposed in one of said compartments for constantly biasing said spindle to a noncompressive position and an inlet opening for flowing the operating fluid into another compartment therethrough,

the lift of said spindle being adjustable for compatibility with engines having different operating conditions.

The result of the experiments conducted on an engine to which the device of the invention was actually applied has revealed that the engine with the device of the invention could be started completely satisfactory with no trouble in the operation of the diaphragm, at the minimum possible rotational speed for starting the engine and within the temperature range from 5 C. to C. It was also confirmed that, according to the present invention, a suflicient amount of oil discharge is ensured at the rated speed, i.e. when the engine is in operation, due to the high rotational speed, even with a slight variation in oil pressure caused by the elevated temperature and also it is possible to secure a required oil pressure at all times owing to the control by the oil pressure regulating Valve.

The device of the present invention will now be described in further detail with reference to the accompanying drawings which illustrate an embodiment of the device according to the invention and in which:

FIGURE 1 is a vertical cross section illustrating in detail the valve rocker arm chamber equipped with a diaphragm;

FIGURE 2 is a vertical cross section of oil pressure regulating valve means; and

FIGURE 3 is a diagram showing the connection of the system operating the device of the invention.

Referring first to FIG. 1, a cylinder head cover 1 shown in part in cross section has a recess on the side of an exhaust valve so as to form a housing for a fluid pressure means. A diaphragm 2 is mounted across the housing with its periphery sealably tightened to said housing together with the body of a hydraulic decompression means by means of bolts 4. Thus, the housing is divided into two compartments, a high pressure compartment A and a low pressure compartment A.

The high pressure compartment is fed with oil pressure through a lubricating oil pipe 5 and the figure shows the state when the compartment is fed with oil pressure. In the outer peripheral wall of a guide 6 for a diaphragm spindle 12 is formed a shoulder on which two dish-shaped discs 7, 7' are secured by a nut 8 with said diaphragm interposed there'between, said disc 7 providing a spring seat. The spindle guide 6 is supported and guided at its sliding portions 9, 9 by diaphragm guide bushings 10, 10 respectively. The downward displacement of the diaphragm is controlled by a stopper ring 11 fixedly mounted on the spindle guide. The diaphragm spindle 12 is extending in an axial hole bored through the spindle guide and in the upper portion of said hole there is provided an internal thread 14 with which an external thread formed on said spindle are engaged. In the top end of the spindle there is formed a groove 16 for engagement with a screw driver so that the displacement of a value to be moved by said spindle may be adjusted by screwing the spindle by said screw driver. The spindle is fixed to the spindle guide by a nut 17. A spring 18 having a spring constant greater than that of the exhaust valve spring is mounted between the spring seat 7 and the aforementioned body 3 in concentrical relation with said spindle so as to bias the diaphragm downwardly as viewed in the figure causing the exhaust valve to be in a state of noncompression, when the high pressure compartment A is not fed with oil pressure. In the figure are shown a packing 19 for the prevention of oil leakage, a bonnet 20 for the body of decompression means, a hole 21 for communicating the interior of the housing A with the atmosphere, the exhaust valve spring 22, an exhaust valve rocker arm 23 and an exhaust valve stem 24.

Referring now to FIG. 2 showing the detail structure of the oil pressure regulating valve, the crank case of the engine, which is shown in part by reference numeral 25,

is formed with a channel 27 through which a pressure oil from a gear pump flowing through a lubricating oil pipe 26 is introduced into the regulating valve and a port 28 through which the used oil is returned to the crank case. The body of the oil pressure regulating valve 31 is mounted on the flat surface 29 of the crank case with a packing 30 intervening therebetween and fixed to said crank case by bolts 32. A ball valve 34 is depressed against a valve seat 33 at a prescribed pressure by a spring 35 which has the other end secured to a spring support 36 provided in an oil pressure regulating bolt 37. The oil pressure regulating bolt 37 is provided with an external thread formed in the entire peripheral Wall and a groove 37 formed in the top end providing for screwing of said bolt by a screw driver to adjust the pressure exerted on the valve seat, and is screwed in the body of the oil pressure regulating valve and fixed thereto by means of a nut 40. The top end of the oil pressure regulating bolt is covered by a valve cover 41 of the oil pressure regulating valve, which cover is mounted on the body of said valve with a packing 42 intervening therebetween. The oil pressure regulating valve is preferably disposed in a position in which it is adjustable most conveniently before the engine operation in accordance with the characteristic values of the gear pump.

Referring next to FIG. 3, the lubricant in an oil sump 43, when the engine is rotated, is drawn through a suction pipe 44 to an oil filter 45 and circulated by a gear pump 46 through a lubricating oil pipe 26 to the oil pressure regulating valve and different sliding portions of the engine.

The lubricant is regulated to a prescribed pressure by the oil pressure regulating valve and introduced into the high pressure compartment A. When the engine rotation has reached a predetermined level, the diaphragm is displaced to the left as viewed in the figure by the elevated oil pressure in the high compression compartment, causing the spindle 12 to move into a position in which it does not interfere with the operation of the exhaust valve, overcoming the bias of the spring 18. As a result, the exhaust valve closes the exhaust port acting under the bias of valve spring 22 through the intermediary of valve stem 24, so that the cylinder of the engine assumes a compressive state and regular explosions occur in the cylinder to start the engine.

According to the present invention, the variation of the lubricating oil pressure caused by a temperature difference of the oil and rotational speed difference of the oil pump as well as the difference based on the special characteristic of the individual oil pump can be completely regulated so as to smoothly operate the noncompression starting device. Moreover, as the diaphragm housing is' provided integrally with the valve rocker arm cover, the whole construction of 'the device can be made very compact.

What is claimed is: 1 .v

1. In an internal combustion engine including a cylinder, an exhaust port communicating with said cylinder, an exhaust valve adapted to open and close said port, a rocker arm chamber, a rocker arm disposed in said chamber and adapted to actuate said valve,,wherein the improvement comprises a housing integral with said rocker arm chamber, a diaphragm dividing said housing into two compartments, a spindle connected to said dia: phragm and operatively connected to said exhaust valve rocker arm, resilient means disposed in one of said cornpartments for constantly biasing said spindle to an exhaust valve noncompression position, an inlet opening formed in the other of said compartments, a source of fluid, means to flow said fluid into said other compartment through said inlet opening, and means to regulate the pressure of said fluid flowing into said other compartment, the amount of fluid passed into said other compartment being such that when the engine rotation has reached a predetermined level, the force of said spring is overcome and said spindle and exhaust valve are re leased to a compressive position to enable the engine to start.

2. The improvement of claim 1, wherein said fluid is in the form of lubricating oil.

References Cited UNITED STATES PATENTS 1,396,418 11/1921 Gilliard 123-482 2,323,304 7/ 1943 Bowman 123182 3,223,076 12/ 1965 Isoda 123-182 FOREIGN PATENTS 908,009 8/ 1945 France.

WENDELL E. BURNS, Primary Examiner. 

